Triphenylcarbinol dyestuffs as photographic antihalation material



United States Patent 3,005,711 TRIPHENYLCARBINOL DYEESTUFFS AS PHOTG- GRAPHIC ANTEIALATION MATERIAL Lothar Burgardt, Leverkusen-Bayerwerk, ()ttmar Wahl,

Opladen, and Helfried Klockgether, Leverkusen, Germany, assignors to AGFA Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No DHlWlHg. Filed Nov. 10, 1955, Ser. No. 546,284

Claims priority, application Germany Nov. 12, 1954 5 Claims. (Cl. 9684) The present invention relates to photographic materials comprising antihalation layers.

For the production (of antihalation layers, it is known to use natural or synthetic resins as binding agents instead of gelatine, so that the layers, although being spar ingly soluble or insoluble in water, can be removed owing to their alkali solubility in the alkaline development or processing baths. Such resins, which can be applied from organic solvents, to the support of the light sensitive layers, are for example described in German Patents 584,- 662, 570,991, and 621,171.

A number of dyestufi groups, including also fuchsone dyestuifs or aurines and benzaurines, have been pro posed as dyestuifs for these antihalation layers. Benzaurine and its derivatives, such as halogenated and sulphonated benzaurines, have also been applied as antihalation layers when dissolved in resin solutions.

However, the said dyestulfs have not proved satisfactory in practice as antihalation dyestuffs, since they either have a deficient solubility in the organic solvents from which they are applied together with the resins, or do not show sufiicient colour intensity in the organic solvents.

A whole series of conditions are required of the antihalation dyestuffs. Apart from the position of the absorption zones, which may vary according to the purpose of use, it is necessary to have good solubility and high color intensity in order to achieve the required absorption values with a minimum of dyestuif concentration and without deleteriously affecting the properties of the layers themselves. Such a deleterious influence can for example consist in an impairment of the resistance of the layers to being wholly or partially transferred to a material which is held in close contact to said layers (transfer printing strength), or in a lowering of the alkali solubility of the synthetic resin. Furthermore, such dyestufis must not discolor or difiuse on to the photographic emulsion layers disposed in contact with the antihalation layer and conversely they must also not be decolorized by the influence of the photographic layer which it contacts, for example when the material is stored for a relatively long period. In addition, it is desirable that the dyestuffs do not impair the eflicacy lot the processing baths, for example do not show any effect on the developer substances, do not color the baths and also do not cause any insoluble residues.

It has now been found that antihalation layers which conform to these requirements can be produced if dyestufls of the following general formula are used in the form of the free dye acids or the internal salts as antihalation dyestuifs:

3,005,711 Patented Oct. 24., 1961 In this general formula:

R R R R represent hydrogen, alkyl, such as methyl; ethyl, propyl, aralkyl, hydroxy, alkoxy, such methoxy, ethoxy, propyloxy,substituted alkyl 'gnoups,v

Dyestuiis falling under the above formula include.

those in which R is:

in which the substituents R R R R R have the same meaning as in the above formula.

In addition to their good solubility and excellent color intensity in organic solvents, such as for example methanol, ethanol, propanol or acetic ester, the dyestuffs of the said structure are characterized by their broadened absorption, which is particularly evident in the lacquer layers described above. Generally speaking, they have two absorption maxima, these being in the green and blue range of the spectrum. Consequently, it is possible with a single dyestuff to produce an eflicacy of the antihalation action over practically the entire visible spectrum, that is to say, from about 400 m to about 650 my.

These dyestufls are preferably dissolved in organic solvents which are compatible with the solution of the resinous binding agent compound to be applied or are directly added to the resin solutions. These dyed resin solutions are then applied in the usual manner and dried.

It is furthermore possible to incorporate these dyestufls in other antihalation layers as for instance those in which the binding agents are not dissolved in the processing bath. Such a. binding agent is her instance gelatine. The dyestufi's may also be. applied to supports of cellulose derivatives or of high molecular condensation or polymerization products. In this case the dyestuifs are dis solved in known manner in solvents which have a swelling action on said supports, whereafter' these solutions are used for dyeing said supports. However, we wish to point out, that the incorporation ofthe dyestuffs into antihalation layer the binding agents of which consist of the above disclosed resins is the preferred mode of realizing the prmentlinvention.

The production of the dyestuffs claimed is elfected by known methods, for example by condensation of two mols of a phenol, cresol, a phenol carboxylic acid etc. with a p-amino-benzaldehyde substituted in a manner corresponding to the general formula to form the leuco compound and oxidation of the leuco compound, for example with nitrite, to form the dye base. Suitable as aminobenzaldehydes are, for example,

p-N-[3-chlorethyl-N-methyl-aminobenzaldehyde, p-N-di B-chlorethyl) aminobenzaldehyde, p-N-di(oxethyl) -arninobenzaldehyde, p-N-methyl-N-oxyethyl-aminobenzaldehyde,

N- fl-diethylaminoethyl) -p-amino-benzaldehyde,'-

such as carboxy-methyl N-methyl-N-p-tolylamino-benzaldehyde.

Furthermore dialdehydes of the N-alkyidiphenylamine, such as p-p'-diformyl-N-ethyl- (or methyl)-diphenylamine, may be used. In case ljniol of the dialdehyde is reacted with 4 mols of a phenol. These dyestufis are distinguished by a very high gray content.

Suitable phenols for the production of the dyestuifs are for instance: phenol, o-chlor'ophenol, o-bromophenol, o-cresol, pyrocatechol, pyrocatechol monomethylether, 2.6-dimethylor 2.6-diethyl-phenol, salicylic acid, o-cresotinic acid, 3-chloroor 3-bromosalicylic acid, 3-nitrosalicylic acid. 7

The dyestuffs claimed can also be used in admixture with other dyestuffs already known for this purpose. This is done for the purpose of Widening the absorption range. Alkali-soluble, natural or synthetic resins or -polycondensation and polymerization products are preferably used as binding agents for the antihalation layers. Examples of polymerization products of this type are: polyacrylic acid, polymethyacrylic acid, polystyrene-carboxylic acid, c'opolyrr'iers of vinyl chloride and acrylic acid, vinyl chloride and maleic acid or 'maleic anhydride, acrylonitrile and styrene-carboxylic acid, styrene and maleic acid.

Erample 1 l g. of a dyestuii of the following constitution:

and 30 g. of a polymerization product of vinyl butyl ether and -nialeic anhydride, which is soluble in an alkaline development bath are dissolved in 1.5 litres of alcohol. After the layer has been applied and dried, there is obtained an antihalation layer having an absorption which extends over the entire blue and green zones of the spectrum as well as apart of the red zone. The two absorption maxima are 575 and 490 my. Owingto the alkali solubility of the binding agent, the layer is dissolved out in the developer bath, the dyestuif being simultaneously decolorized.

The above dyestufl? is obtained as follows:

- 21 *g. of o-chlor-p-diethylaminobenzaldehyde (1 mol), 33.5 g. of o-cresotinic acid (2 inol) are added to 175 g. of 90% sulfuric acid, the mixture is agitated for 10 hours at 15 20" and then for 10 hours at 25-30 C. Thereafter, 100 g of monohydrate are added. To the mixture there are added during 5 hours at l520 in small charges 3.5 g. sodiumnitrate. After agitating the reaction mixture for 15 hours at 2025 C., it is poured into 1.2 litres of water, the precipitate sucked off, washed withwater until neutral and dried under diminished pressure at 50-60" C. Yield 54 g. V I

4 Example 2 A dyestufi of the following constitution: E

can also be used instead of the dyestufi mentioned in Example l. v v V This dyestuif is prepared by a process analogous to th'atof Example 1 by condensation of 33.5 g. of o-cresotinic acid and 26.5 g. of N-methyl-N-(p-'-ethoxy-phenyl)- p-aniino-benzaldehyde. The latter may be prepared according to the method of Vilsrneier and Haack (Ber. 60; After recrystallization from alcohol it melts at l21-123 C. The dyes-tuft has an absorption which extends over the whole visible spectrum and part of the ultraviolet spectrum. Absorption maxinra: 560 and 470 are dissolved in 1.5 litres of a 3% alcoholic solution of the resinous condensation product of phenoxy-acetic acid and p-cresol dialcohol which is soluble in alkaline development bath and applied with this solution in known man'- ner as the backing layer to a layer support. The dyestuff is obtained according to Example 1 by condensing 33.5 otcresotinic acid and 14.9 g. of p-diniethylarninobenz'aldehyde. V

V Exzimple 4 15 g. of a dyestuif having the following constitution:

are dissolved in 1.5 litres of a 2% ethanolic solution of a polymerization product of vinyl ethyl ether and maileic anhydride which is soluble in an alkaline development bath and applied as the backing layer to a support carrying a silver halide layer in the usual manner. The back ing layer has a violet color and an absorption region from about 400 to about 620 mu.

The dyestuff is obtained in the following manner:

7.0 g. of p-(N-butyl N w-chlorethylamino)benzaldehyde and 30.5 g. of salicylic acid are condensed as in Example 1 in 175 g. of 20% sulfuric acid and oxidized with 3.5 g. of sodiumnitrite after addition of 100 g. of monohydrate.

The above aldehyde is obtained according to the process disclosed in German specification No. 711,665.

Example A good antihalation effect, the efficacy of which extends over the entire range of sensitivity of a panchromatic film, is obtained in the following manner:

1.5 litres of a 3% alcoholic solution of the resinous condensation product of phenoxy acetic acid and formaldehyde have dissolved therein:

and also 1.5 g. of a green dyestuft' of the following constitution:

6 Example 7 If the two dyestuffs of Example 5 are replaced by 840 g. of a dyestuff of the formula:

HOOC

I OH I CH3 H3 an antihalation action is obtained, which extends over the whole visible spectrum.

This dyestufi is prepared as follows:

12.7 g. N-ethyl-p-p'-diformyldiphenylamine and 33.5 g. of o-cresotinic' acid are condensed as described in Example 1 in 175 g. of 90% sulfuric acid and oxidized with 3.5 g. of nitrite after addition of 100 g. of monohydrate. Yield: 44 g.

The solution is applied to the back of a support the front-side of which carries a silver halide emulsion layer in the usual way and dried. The absorption of this layer extends over the entire range of the visible spectrum and into the infra-red range.

The dyestuflf of the first formula is prepared according to Example 1 by condensation of 17.7 g. of p-diethylaminobenzaldehyde and 33.5 g. of o-cresotinic acid.

Example 6 Instead of the dyestuif of Example 4 a dyestuif of the following formula may be used:

I OH

It 0%; \CH:

boon

The dyestuff is produced as in Example 1 using:

19.3 g. of N-methyl-N-w-carboxymethylaminobenzalde hyde (melting point ZOO-202 C.), 18 g. of o-chlorophenol. It is of intensive red color.

N-ethyl p-p-diformyldiphenylamine is prepared as follows:

240 g. of phosphorus oxychloride and 150 g. of dimethylformamide are mixed with cooling.

After one hour 100 g. of ethyldiphenylamine are dropped into the mixture which is stirred at C. for five hours and introduced into water at 40 C. After several hours stirring the resultant oily aldehyde solidifies. The aldehyde is filtered off with suction and recrystallized twice from alcohol. Yield: g. (M.P. 73-74 0).

7 emulsion layer and an antihalation layer containing a 4. A photographic light-sensitive material comprising light-absorbing dyestufl? having the formula: a film support having thereon a light-sensitive silver halide Cm OH: emulsion layer and an antihalation layer containing a I H I light-absorbing dyestufi having the formula; 11000 -on 5 I i on; 0H1; H000 (:1 COOH I Q H0 CGOH a 1100:: 00011 C2415 OzHs 2. A photographic light-sensitive material comprising N a film support having thereon a light-sensitive silver 15 halide emulsion layer and an antihalation layer contain- 7 9155 E mg a hghbabsorbmg dyesmfl having the formula 5. A photographic light-sensitive material comprising (3H3 OH 7 CH3 a film support having thereon a light-sensitive silver halide 1 emulsion layer andan antihalation layer containing a G? OH 29 light-absorbing dyestulf having the formula:

HOOQ 00 OH 7 CH1 OH;

I n; HOOO -01; N-CHs: 1 g

a a 7 Boos 00H 3. A photographic lightrsensitive material, comprising 7 a film support having thereon, a light-sensitive silver 1 H000. 000E halide emulsion layer and an .antihalation layer containing a light-absorbing dyestuff' having the formula: Q C

. 40 H000 (7093 References Citecl in the file of this patent UNITED STATES PATENTS 1,747,541 'Francke Feb. 18, 1930 N 2,350,090 Beilenson May 30, 1944 g 2,462,534 Murray Feb. 22, 1-949 1 FOREIGN PATENTS 0 1 1,001,943 Francei Oct; 3-1,, 1951 

1. A PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL COMPRISING A FILM SUPPORT HAVING THEREON A LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER AND AN ANTIHALATION LAYER CONTAINING A LIGHT-ABSORBING DYESTUFF HAVING THE FORMULA: 